Apple launched the new iPhone models iPhone 6s and 6s Plus last month on 9th September in an event. When apple launched the iPhone 6s Plus it was sold with four model numbers called A1634, A1687, A1690 and A1699. As per PCMag, out of these, A1699 is currently selling in China, A1634 is sold by T-mobile and AT&T in US for lease and A1687 CDMA is sold by Verizon and T-Mobile. The regional model A1690 is still not available for sale.
iPhone 6S Plus A1690 was also certified by FCC and now, looks like Apple will start selling it soon. The Apple A1690 model of 6S Plus is recently being certified in China by TENAA. The phone has same specifications like other iPhone 6S Plus models but it may have some carrier limitations.
The TENAA listing (added 16th October) for Apple A1690 model of iPhone 6S Plus shows the specifications, that we already know, including a 5.5-inch TFT (1080 × 1920 pixels) display with 1.8GHz Dual core A9 processor and 16 GB of inbuilt storage. It runs on pre-installed iOS 9.0 OS with an 8-megapixels or 12-megapixels rear iSight camera and a 1.2 MP front camera.
It will be interesting to see for which region this model of iPhone 6S Plus will be used by Apple. Stay tuned.
Source: TENAA(translated)